The present invention relates to a control and communication system for railway trains, particularly to railway trains of so-called high composition, that is to say comprising a large number of carriages or wagons.
Conventionally, a railway train brake control is actuated pneumatically and in the case of trains with a large number of carriages or wagons can give rise to problems both because of the limited speed of propagation of the required braking information along the so-called general duct (a speed which must not be less than 250 m/sec- and which is, however, usually less than 300 m/sec), and above all because of the slow rate at which the pressure in the auxiliary reservoirs of the individual carriages or wagons is re-established via the general duct during braking.
These problems mean that for very long trains in transit on tracks characterised by significant inclinations, braking becomes practically ungovernable, to the point of reducing the operating speed to values incompatible with the requirements of an optimum use of the lines.
In the case of railway trains with a large number of carriages or wagons it is often necessary to have recourse to locomotives or supplementary engines ganged together at the front of the train, or in intermediate positions and/or at the tail. This arrangement involves in each case the adoption of arrangements to ensure the operating synchronisation of the various locomotives or engines both during the driving phase and in the “coasting” phase as well as during imposed braking (braking of the diesel or electric motors of the engines). The operating synchronism between various motors remote from one another is commonly achieved by human supervision of each traction machine: the driver of each auxiliary engine communicates, usually by way of radio telephone, with the driver of the leading locomotive (main engine) and receives suitable instructions on the manoeuvres to perform. This arrangement involves working inefficiencies, loss of time and easily imaginable potential manoeuvring errors.
Only for certain determined trains, generally those adapted for passenger services, has there been proposed the use of hard wired remote control systems for automatically co-ordinating the operation of the various locomotives or engines of a train.
In very recent times experimental applications have been tried in which recourse has been made to communication systems along the train with the use of twin wire supports. Such applications, however, run into problems associated with the quantity of transmissible information. In other experiments problems related to the quantity of information have not arisen, the need for use in high composition trains, to introduce repeater apparatus which is intrinsically rather expensive has been demonstrated.